Carbon Nanotube Reinforced Composites: Metal and Ceramic ...

Figure 2.27 TEM image of electrodeposited Ni/MWNT
nanocomposite showing uniform distribution of CNTs.
Reproduced with permission from [102]. Copyright Ó (2008)
Elsevier.
a mean grain size of 28 nm (Figure 2.28). The formation of nanograins coupled
with CNT reinforcement lead to the enhancement of mechanical properties as
expected.
Compared with d.c. deposition, pulse-plating and pulse-reverse plating facilitate
larger amounts of filler incorporation into the matrix of metal-matrix nanocomposites
under the same current density [103, 104]. For example, the maximum
alumina incorporation in nickel and copper matrix using direct current method
is 1.5 wt% and 3.5 wt%, respectively. However, a maximum incorporation of
5.6 wt% alumina in a copper matrix can be achieved by pulse plating [103]. Sun et al.
used deposited Ni/SWNTand Ni/MWNTnanocomposite coatings in the Watt bath
solution using d.c. and pulse-reverse plating methods [105]. As expected, the d.c.
method produces uneven surface coating with many deposit protrusions. The
coatings formed by the pulse-reverse method exhibit good interfacial bonding
between CNTs and the metal matrix. Guo et al. demonstrated that higher pulse
frequency and higher pulse reverse ratio employed during electrodeposition of
Figure 2.28 TEM dark-field image showing formation of Ni
nanograins (28 nm) in Ni/MWNT composite prepared by
electrodeposition. Reproduced with permission from [102].
Copyright Ó (2008) Elsevier.
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